The present invention relates to an assembly controlling the insertion and movement of an instrument assembly.
Such instruments may be, for instance, obturators and are frequently employed in many ways in endoscopic examinations and treatments.
In a number of endoscopic examinations and treatments, endoscopic shafts are required which are provided with an insulation from the inserted instrument. The insulation can be in the form of a small tube or tubelet. For reasons of sterilization, thermal resistance, etc., it is advantageous for this insulating tubelet to be made of a ceramic material. It has turned out, however, that ceramic material tends to crack and break during work with the endoscopic shafts for reasons which could be explained in very rare cases only. A more detailed explanation is not necessary of the fact that such cracking and breaking of the ceramic material is extremely bothering, for instance, when this happens during an endoscopic examination of the knee or in similar operations. Thus, in spite of the foregoing disadvantages, plastic tubelets have been commonly used as insulation material.
It is thus an object of the present invention to provide an assembly which permits the use of a protective ceramic tubelet or protective coating of ceramic material on the interior shaft without cracking or breaking when used with an instrument assembly inserted into the shaft. It is a further object to provide such a ceramic tubelet or ceramic material protection to a shaft, such that there will be no interference to the normal operation of the instrument assembly inserted into the shaft.
These objects and other objects are achieved by providing an insertion assembly for Controlling the insertion and movement of an instrument assembly in a shaft in which the instrument assembly is of the type bendable by an actuator device. Instrument locking elements are provided which prevent movement or allow movement of the instrument assembly relative to the shaft according to a given position of the instrument locking elements. Actuator locking elements are provided which are movable between a position allowing bending of the instrument assembly and preventing bending of the instrument assembly. When the instrument locking elements prevent movement of the instrument assembly relative to the shaft, the actuator locking elements allow bending of the instrument assembly by the actuator device. When the instrument locking elements are moved into the position permitting movement of the instrument assembly relative to the shaft, the actuator locking elements prevent bending of the instrument assembly.
According to the present invention, it was found that the main reason of cracking and breaking of the ceramic material used for insulating tubelets occurred during the insertion of the instrument assembly through the shaft, during removal of the instrument assembly through the shaft, or whenever the instrument assembly was moved with respect to the shaft. Once the instrument assembly is in place in the shaft, the normal operation of the instrument assembly, such as during bending, was found not to cause cracking of the ceramic material. It was found that when the actuator device bent the instrument assembly during movement of the instrument assembly relative to the shaft, the bent portion of the instrument assembly pressed against the ceramic material and thus caused the insulation to crack and break.
The present invention provides a system in which the actuator device will be prevented from bending the instrument assembly when the instrument assembly is allowed to move relative to the shaft. However, when the instrument assembly is prevented from moving relative to the shaft, the actuator device will be permitted to bend the instrument assembly. Thus, during movement of the instrument with respect to the shaft, the instrument assembly cannot be bent and thus cannot cause the cracking and breaking previously experienced when the assembly was bent during movement relative to the shaft. Further, once the instrument assembly is prevented from moving relative to the shaft, such as when normal operation of the bending of the instrument assembly is desired, the actuator element will be permitted to bend the instrument assembly.
According to advantageous features of certain preferred embodiments of the invention, the instrument locking elements include a locking ring which is rotatable between a first position in which the instrument assembly is locked relative to the shaft and a second position in which the instrument assembly is unlocked relative to the shaft. In certain preferred embodiments, the actuator locking elements are moved into a first position, allowing bending of the instrument assembly when the locking ring is moved into the first position, preventing movement of the instrument assembly relative to the shaft. Further, the actuator locking elements are moved into a second position, preventing bending of the instrument assembly when the locking ring is moved into the second position, allowing relative movement between the instrument assembly and the shaft. Thus, without any additional operation being required, the instrument assembly cannot be moved relative to the shaft with the front section being bent off, since when relative movement of the instrument assembly and the shaft is allowed, the actuator device will automatically be prevented from bending the instrument assembly.
It is also contemplated to use a basic inventive idea underlying the invention, i.e., the idea of employing the rotation of an insertion locking ring for locking or release of an actuator element as well, for instruments in which the front section of an instrument is bent by means of an electromagnetic mechanism, in which the actuator element merely controls the excitation by electric current.
It is further contemplated to use the present invention for instruments in which a mechanism is provided to transfer the motion from the actuator element to the front section of an instrument. In certain preferred embodiments, this mechanism includes a guiding element having an actuating rod element slidingly disposed therein. Further, a stationary supporting element is fixedly attached to the guiding element The stationary supporting element and the actuating rod element are fixedly attached to a front section of the instrument assembly. The actuating rod element can be moved back and forth with respect to the guiding element, thereby providing bending of the front section of the instrument.
According to other advantageous features of certain preferred embodiments of the invention, a locking ring is provided with an inner circumference which surrounds the guiding element. A pin element is disposed in the guiding element in between the actuator rod element and the inner circumference of the locking ring. In one position, the inner circumference of the locking ring locks the pin in between the locking ring and the actuator rod element, thereby preventing bending. In another position, the pin is not locked between the actuator rod element and the locking ring, thereby allowing bending.
In certain preferred embodiments, the inner circumference of the locking ring includes a contour service such that upon rotation of the locking ring into one position, the contour moves toward the actuator rod element, thereby locking the pin between the actuator rod element and the inner circumference of the locking ring. As the locking ring is rotated out of this position, the contour surface moves away from the actuator rod element, thereby unlocking the pin element from the actuator rod element.
According to other advantageous features of certain preferred embodiments of the invention, a spring element is provided for biasing the pin against the inner circumference of the locking ring. In certain other embodiments, a ball-shaped element is disposed between the pin element and the inner circumference of the locking ring. In other preferred embodiments, an actuator rod spring element is provided for biasing the actuator rod element into a position such that the instrument assembly is unbent. All of these features enhance the operational reliability of the present invention.
According to other advantageous features of certain preferred embodiments, the instrument assembly used includes a rigid bevelled region immediately proceeding the bendable front section. The rigid bevelled region is disposed on each side towards which the front section is bent. In these embodiments, a force introduced into the instrument, as it may arise in the bending operation, will be precluded from creating another cause of destruction of a shaft insulated with ceramic material. In conventional instruments, without this bevelled region, the force introduced upon bending may cause parts of the instrument to bear against the ceramic shaft.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.